We need locking Since the build servers use a shared download dir
and multiple vservers might want download same file at same time.

fixes #873

So we can set pkgname if it differs from download archive name

curl does not fail by default. it downloads the 404 error page instead
so we need add -f option to curl.

Not been used for ages.

fixes #871

This is to avoid things like:
http://git.alpinelinux.org/cgit/aports/commit/?id=81c0a4bb37e709ebc5add8394331d28209a61b6f

apk takes files that starts with - as params.

build-list will list which aports that has missing packages

rebuild-list will list which aports that has outdated packages, i.e. when
APKBUILD is newer than the apk

We alos introduce $langdir where you can set other dir to look for
localization dirs.

So we can fish out the maintainer from given aport

if there are an APKBUILD in current dir, then use ../ as repodir.
Otherwise, use cwd as repodir.

Introduces requirement of lua-filesystem

This might happen if package name appears as a dependency but there
are no apkbuild for it.

we might have '.' in pkgname as in gtk+2.0

To be allowed to keep the .la files you need to add 'libtool' to
$options